Technique of Estimation of Actual Strength of a Gas Pipeline Section at its Deformation in Landslide Action Zone

The technique is given which permit to determine stress and strain state (SSS) and to estimate actual strength of a section of a buried main gas pipeline (GP) in case of its deformation in landslide action zone. The technique is based on use of three-dimensional coordinates of axial points of the deformed GP section. These coordinates are received by full-scale survey. The deformed axis of the surveyed GP section is described by the polynomial. The unknown coefficients of the polinomial can be determined from the boundary conditions in points of connection with contiguous undeformed sections as well as by use one of minimization methods at mathematical processing of full-scale survey results. The received form of GP section’s axis allows to determine curvatures and, accordingly, bending moments along all the length of the considered section. The account for the influence of soil resistance to longitudinal displacements of a pipeline is used to determine longitudinal forces. Received by this technique values of bending moments and axial forces as well as known value of internal pressure are used to receive all necessary components of actual SSS of pipeline section and to estimate its strength by elastic analysis.